I pulled the trigger on my Winchester M70 243 heavy barrel rifle. Fortunately I was wearing glasses and felt the powder vapors hit my face and along with the extra loud boom. I was not hurt but could not open the bolt until I found a 2X4 and tapped the bolt open. Out comes the round "welded" to the bolt. Then I noticed that the front of the brass "neck" was no longer there. I looked up the barrel and did not notice the neck stuck in the chamber. I pried off the shell from the bolt and the primer dropped out and the primer pocket was enlarged. The base of the shell had and exact imprint of the bolt face. My gunsmith check out my rifle and declared it ok. He told me I was lucky. Not sure what had happened as it could have been a double load or light load that exploded. I weighted and pulled all the rounds that I had reloaded. Apparently that was the only one that I had a problem with. Scarred the living daylights out of me. Lemmon